From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
This patch adds top level BSG support to QEMU-KVM block and adds the
BDS_* prefixed defines for SG_IO and BSG.
It adds the BDS_SCSI_GENERIC and BDS_BSG assignments in block/raw-posix.c:hdev_open()
using S_ISCHR() and major(st.st_rdev) in order to determine when we are dealing with
scsi-generic or scsi-bsg backstores.
It also adds a special case BSG check in find_protocol() using the BSG
major in order to avoid the strchr() for ':' as we expect filenames to
contain /dev/bsg/H:C:T:L.
This path also adds a struct BlockDriverState->fd to save a opened file descriptor
with format_name = 'raw' for use by scsi-bsg.
Signed-off-by: Nicholas A. Bellinger <nab@xxxxxxxxxxxxxxx>
---
block.c | 23 ++++++++++++++++++++---
block.h | 1 +
block/raw-posix.c | 17 +++++++++++++++--
block_int.h | 5 +++++
4 files changed, 41 insertions(+), 5 deletions(-)
diff --git a/block.c b/block.c
index 88dbc00..3cd18ec 100644
--- a/block.c
+++ b/block.c
@@ -285,8 +285,12 @@ static BlockDriver *find_protocol(const char *filename)
{
BlockDriver *drv1;
char protocol[128];
- int len;
+ int len, bsg = 0;
const char *p;
+#if defined(__linux__)
+ struct stat st;
+#endif
+
/* TODO Drivers without bdrv_file_open must be specified explicitly */
@@ -296,7 +300,15 @@ static BlockDriver *find_protocol(const char *filename)
return bdrv_find_format("file");
#endif
p = strchr(filename, ':');
- if (!p) {
+#if defined(__linux__)
+ if (stat(filename, &st) < 0)
+ return NULL;
+ /* This is not yet defined in include/linux/major.h.. */
+ if (S_ISCHR(st.st_mode) && major(st.st_rdev) == 254)
+ bsg = 1;
+#endif
+
+ if (!p || bsg) {
drv1 = find_hdev_driver(filename);
if (!drv1) {
drv1 = bdrv_find_format("file");
@@ -1209,7 +1221,12 @@ int bdrv_is_read_only(BlockDriverState *bs)
int bdrv_is_sg(BlockDriverState *bs)
{
- return bs->sg;
+ return bs->sg == BDS_SCSI_GENERIC;
+}
+
+int bdrv_is_bsg(BlockDriverState *bs)
+{
+ return bs->sg == BDS_BSG;
}
int bdrv_enable_write_cache(BlockDriverState *bs)
diff --git a/block.h b/block.h
index f87d24e..4faeedc 100644
--- a/block.h
+++ b/block.h
@@ -146,6 +146,7 @@ int bdrv_get_translation_hint(BlockDriverState *bs);
int bdrv_is_removable(BlockDriverState *bs);
int bdrv_is_read_only(BlockDriverState *bs);
int bdrv_is_sg(BlockDriverState *bs);
+int bdrv_is_bsg(BlockDriverState *bs);
int bdrv_enable_write_cache(BlockDriverState *bs);
int bdrv_is_inserted(BlockDriverState *bs);
int bdrv_media_changed(BlockDriverState *bs);
diff --git a/block/raw-posix.c b/block/raw-posix.c
index 1515ca9..d349109 100644
--- a/block/raw-posix.c
+++ b/block/raw-posix.c
@@ -52,6 +52,7 @@
#include <sys/ioctl.h>
#include <linux/cdrom.h>
#include <linux/fd.h>
+#include <linux/major.h>
#endif
#if defined (__FreeBSD__) || defined(__FreeBSD_kernel__)
#include <signal.h>
@@ -843,6 +844,9 @@ static int hdev_probe_device(const char *filename)
static int hdev_open(BlockDriverState *bs, const char *filename, int flags)
{
BDRVRawState *s = bs->opaque;
+#if defined(__linux__)
+ struct stat st;
+#endif
#ifdef CONFIG_COCOA
if (strstart(filename, "/dev/cdrom", NULL)) {
@@ -873,8 +877,17 @@ static int hdev_open(BlockDriverState *bs, const char *filename, int flags)
s->type = FTYPE_FILE;
#if defined(__linux__)
- if (strstart(filename, "/dev/sg", NULL)) {
- bs->sg = 1;
+ if (stat(filename, &st) < 0) {
+ printf("stat() failed errno: %d\n", errno);
+ return -1;
+ }
+ if (S_ISCHR(st.st_mode)) {
+ if (major(st.st_rdev) == SCSI_GENERIC_MAJOR) {
+ bs->sg = BDS_SCSI_GENERIC;
+ } else if (major(st.st_rdev) == 254) {
+ /* This is not yet defined in include/linux/major.h.. */
+ bs->sg = BDS_BSG;
+ }
}
#endif
diff --git a/block_int.h b/block_int.h
index 1a7240c..74bcb1a 100644
--- a/block_int.h
+++ b/block_int.h
@@ -40,6 +40,10 @@
#define BLOCK_OPT_CLUSTER_SIZE "cluster_size"
#define BLOCK_OPT_PREALLOC "preallocation"
+#define BDS_NONE 0
+#define BDS_SCSI_GENERIC 1
+#define BDS_BSG 2
+
typedef struct AIOPool {
void (*cancel)(BlockDriverAIOCB *acb);
int aiocb_size;
@@ -141,6 +145,7 @@ struct BlockDriverState {
int encrypted; /* if true, the media is encrypted */
int valid_key; /* if true, a valid encryption key has been set */
int sg; /* if true, the device is a /dev/sg* */
+ int fd; /* Used for BSG file descriptor */
/* event callback when inserting/removing */
void (*change_cb)(void *opaque);
void *change_opaque;
--
1.5.6.5
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